JP2003523493A - Simultaneous combustion of waste sludge in municipal waste combustion equipment and other furnaces - Google Patents

Abstract

A system and method for treating, injecting and co-combusting sludge in a municipal waste or other combustor is disclosed. The system includes a sludge receiving and treatment module and a sludge injection and combustion module. The sludge is received and stored in one or more storage hoppers where it is first diluted with a liquid and subsequently mixed to a desired homogeneous consistency suitable for pumping. The high liquid content sludge is then pumped to a furnace injection nozzle where it is preferably atomized with steam and sprayed into the combustion zone of the furnace. The disclosed system and method increases sludge moisture content and controls the solids content of the sludge to control furnace temperature.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION

This application claims the benefit of US Provisional Application No. 60 / 104,806, dated October 19, 1998.

The present invention relates to municipal solid waste combustion devices (MWCs), and, in a broad sense, all steam power boilers and other furnaces. The present invention is waste sludge of varying solids content, including municipal wastewater sludge, paper mill sludge, and other industrial sludge in MWC power boilers and other furnaces that incinerate municipal solid waste or other fuels. Including handling and processing by pyrolysis of

[0003]

[Prior art]

With fewer and fewer options available to communities and industries for sludge treatment, there is a great need to develop new cost-effective and environmentally friendly treatment methods. In the 1950s and 1960s, sludge was often incinerated in multiple hearth furnaces. However, most of these installations have weak burning power and emit very harmful air. Therefore, this method has been largely discarded and, instead, non-combustion processing techniques have been used.

Co-combustion of sludge with other fuels, which is preferably high carbon content sludge, has been unable to reach the goal for many years. One method that has been repeatedly discussed in the technical literature is to design an external heat dryer to pre-dry the sludge before it is injected into the furnace so that it does not have to be dried in the furnace. is there. However, this technique is costly and even dangerous. This is because inhaling dust from the furnace is potentially harmful to health and there is a risk of dust explosion.

In another method described below, liquid-containing sludge is injected into a modern combustion process. The techniques of these methods were not commercially accepted. Because,
The scope of application was limited, the cost was high, and there were technical defects.

[0006] Komline et al., In US Pat. No. 3,322,079, used hot gas generated by the combustion of municipal solid waste (MSW) to dry sludge injected into a furnace by a rotary centrifugal atomizer. Attention is paid to the synergistic effect of the co-combustion of the sludge used and the municipal solid waste (MSW). However, the operating costs of such a device are high and it is difficult to reliably maintain the disclosed rotary centrifugal atomizer due to clogging and wear. The rotary atomizer emits a considerable amount of large particles that do not burn completely, which creates a problem of cinder deposits inside the boiler.

Dingwell uses steam to atomize waste oil in a burner designed to extend to the combustion chamber in US Pat. No. 3,838,651. But,
This invention can only be used for waste oil in old-fashioned incinerators that were not strictly regulated at the time of the invention. Partial combustion was allowed,
Compliance with regulations was not the goal. The steam was used to atomize, but non-oil, ie, aqueous sludge, was not treated.

Pan in US Pat. No. 3,903,813 developed a device for injecting steam atomized sludge into a combustion chamber located near an oil or gas burner. By using the above injection device, it is possible to mix pressurized fluid and sludge in the same pipe. In this case, the mixture is discharged through a narrow orifice at the end of the discharge pipe, so that the mixture is
It is released to the atmospheric pressure inside the furnace containing oil or gas. Co-combustion of MSW and other renewable fossil fuels has not been considered and the equipment is mainly 5
It was intended to treat sludges containing% or less solids. The sludge injection location is limited to the area below the flame of the oil or gas burner. The purpose of this device was to burn only the sludge with an oil or gas burner.

Carpenter, in US Pat. No. 5,284,405, discloses a method for including sludge particles in a stream of compressed combustion air. However, this invention
Can only be used for combustion in rotating cement kilns. No attempt has been made to burn suspended sludge, nor has it considered compliance with regulations.

[0010] Goff et al. In US Pat. No. 5,052,310 and US Pat. No. 5,405,537 atomize the sludge spraying into the furnace through the nozzle and reduce the efficiency of the boiler due to the liquid in the sludge. In order to offset this, we have invented a sludge injector for MWC that uses oxygen-enriched air. However, in the case of this device, it was expensive to build an oxygen generation plant adjacent to the owner's central production facility, and in the case where such a plant was not built, it was packed in a large number of containers. You have to buy oxygen. Moreover, the invention can only be used for MWC and must modify current combustion air control systems.

Mole, in US Pat. No. 5,531,169, injects liquid waste, which is primarily acid contaminated, adjacent to a main fuel burner. The main purpose of this device is to separate the acid molecules. The purpose of this device relates to air rather than steam atomization, and the present invention aims to treat liquid hazardous waste rather than sludge treatment and combustion of non-hazardous municipal solid waste and conventional power generation. I am trying.

Guibelin in US Pat. No. 5,544,598 discloses a nozzle for treating a slurry such as pasty waste or fat-containing waste by spraying on burning municipal solid waste. developed. However, this device cannot handle sludge and is not designed to atomize particles for combustion in suspension.

[0013]

[Problems to be Solved by the Invention]

It is an object of the present invention to treat sludge with a wide range of properties (comprising varying amounts of water and solids components) and to provide a constant flow of sludge to the injection device. It is to provide a processing device. Prior art devices were not designed to and could not treat sludge of varying homogeneity and sludge of varying solids content.

Another object of the present invention is to facilitate the treatment of sludge, which typically contains solid components in an amount of 15% or more.

Yet another object of the present invention is to improve the efficiency of floating combustion of sludge particles to a maximum extent, so that virtually no larger sludge particles are incinerated.

Yet another object of the present invention is to provide a sludge pre-combustion treatment process comprising:
Utilizing wastewater, other industrial process effluents, air pollution control slurries, or mixtures thereof.

[0017]

[Means for Solving the Problems]

The above objectives, goals and goals are achieved by the present invention for injecting sludge into a combustion device for treating sludge and substantially reducing or completely eliminating the drawbacks that limited the feasibility of the prior art. To be done.

The present invention typically comprises a sludge receiving / treatment module and a sludge injection / combustion module. The sludge receiving / treatment module receives the sludge and dilutes it with a liquid, thereby increasing the water content of the sludge, and the sludge injection / combustion module places the diluted sludge into the combustion zone of the combustor. To jet. In this combustion zone, the diluted sludge is burned in a floating state. The sludge injection / combustion module atomizes the diluted sludge with steam and sprays the atomized diluted sludge into the combustion zone of a combustor that contains municipal solid waste or other combustion therein. Therefore, the atomized diluted sludge burns suspended above municipal solid waste or other fuels.

In a preferred embodiment of the present invention, the sludge is received in a sludge receiving / treatment module and stored in one or more storage hoppers, in which the water, plant, Diluted with diluents such as wastewater, other industrial waste solutions, pollution control slurries or mixtures thereof. The size of the sludge particles is then subdivided and the sludge is mixed into a homogeneous state suitable for pumping.
The liquid-rich sludge is then pumped to the jet nozzle of the furnace, preferably where it is atomized with steam and sprayed into the combustion zone of the furnace.

The steam atomization nozzles used in the present invention are specifically configured to be flash dried to reduce their maximum particle size when the sludge contacts the atomized steam before being injected into the furnace. . It allows for near complete combustion, with little or no effect on bottom ash quality and burnout, and with current air pollution control devices, the treatment of virtually all products of sludge combustion. Done. In the conventional invention, the goal of floating combustion could not be achieved.

The present invention is configured to increase the number of potential sludge customers as much as possible and to send, modify and control the solids content to stabilize the temperature of the furnace in response to fluctuating primary fuel heat values. Has been done.

Unlike conventional devices, the present invention unexpectedly increases the water content of sludge (to the extent that the liquid used contains water) as a means of controlling the temperature of the furnace. By lowering the temperature of the furnace, more primary fuel can be added, resulting in
Revenues at facilities receiving money to receive the above fuels, such as municipal waste combustors and biomass combustors, will increase.

In the case of MWCs, the heat value of MSW varies seasonally and hourly depending on the source of solid waste. Using the present invention, the flow rate can be manually adjusted to keep the characteristics of the sludge containing solids and carbon and the temperature in the furnace relatively constant, resulting in a smoother steam generation. become. In addition, many M
Since the mean heat value of MSW has risen significantly since the WC was designed, solid waste throughput has been limited by the higher heat value of the fuel. Solid waste is MW
As C is a major source of revenue, lower processing power may result in lower revenue. Using the disclosed method, MWC throughput revenue can be maintained above the heat value of the design MSW.

The present invention provides for the inclusion of solids in any range so long as the sludge can be diluted by adding water-based solutions and / or other liquids such as industrial process effluents and antifouling slurries. It can be applied to sludge containing amounts, and the size of solid particles in the sludge can be reduced by stirring and atomizing. The present invention, after dilution, is designed to burn sludge containing solids in the range of 5-15%. Therefore, when used for commercial applications, excellent control and reliability can be achieved.

For all industrial combustion facilities, the present invention can treat plant effluents and other industrial treatment effluents, reducing the overall cost of air pollution control.

In the case of industrial sludge generators, such as paper mills and other similar facilities, the present invention provides that sludge transportation and disposal costs to controlled landfill sites continue to increase. Existing conventional fuel real-time steam boilers can be used for environmentally friendly on-site or localized sludge treatment.

Preferred embodiments of the sludge treatment and injection device of the present invention, as well as other objects, features and advantages, can be understood by reading the following detailed description with reference to the accompanying drawings. .

[0028]

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows two modules, a sludge receiving / treatment module 20.
FIG. 1 is a general view of a suitable sludge treatment and injection device 100 with 0 and sludge injection / combustion module 300. If desired, the sludge receiving / treatment module 200 can be installed physically separate from the sludge injection / combustion module 300. Also, all or part of the sludge receiving / processing module 200 can be incorporated within a mode for shipping sludge, such as a special truck that dilutes and premixes the sludge during transportation. However, the preferred apparatus 100 of FIG. 1 includes both modules in the field, along with a municipal waste combustor (MWC), power boiler or other furnace.

In the preferred embodiment 100, the sludge is delivered to the sludge receiving / treatment module 200 by conventional methods such as trucks or pipelines. When shipped by truck, the sludge can be processed in batch mode or stored until a sufficient amount for the semi-continuous type. When the sludge is carried continuously, such as by pipeline transport, the device can easily operate in continuous process mode.

In either mode, the input sludge with different water contents, usually in the range of about 5 to 50%, preferably in the range of 15 to 45% solids, is placed in the closed hopper 1. Be accommodated. It is preferable that the configuration of the closed hopper 1 enables supply and storage of sludge without being odorless and without human intervention. Depending on the amount of sludge input and the mode used, either continuous or batch processing, multiple hoppers can be installed to prevent overflow. A variable speed screw conveyor 2 located at the bottom of the hopper 1 sends the sludge to a variable speed rotating drum mixer 3, which also includes water, plant effluent, other factory treatment effluent, air pollution control slurry, or the like. Diluting liquid, which may include the mixture, is received through line 4. The solid component transfer device 5 adjusts the speed of the variable speed drive 7 to control the amount of solids sent from the screw conveyor 2 to the drum mixer 3, that is, the solid controller 6 set by the operator, that is,
Supply continuous read data to the control panel. The solids controller 6 also opens and closes the dilution valve 8 as needed to add dilution liquid to maintain the required amount of solids in the drum mixer 3. The required optimum solids content in the sludge is about 10%, but the amount can range from about 5 to 15% after dilution. Within this range, the treatment can be performed most easily, and at the same time, the sludge can be effectively burned. The stored sludge with a solids content of 5-15% can be bypassed to the mixer 3 and discharged directly from the hopper 1 to the sludge pump suction tank 10.

Weighing and mixing in the drum mixer 3 prior to sending to the next step of the device
It is preferably carried out in a batch process in which the input sludge is mixed with a diluting liquid so that the solids content is at the required level. By doing so, maximum flexibility can be achieved in establishing the required solids content from the widest possible range of sludge properties.

Further, the average heat value of the MSW may be lower than the usual numerical value. This usually occurs when heavy rainfall occurs, which results in a higher moisture content in the MSW. While this is happening, injecting a sludge mixture with a higher heat value helps stabilize the furnace temperature. When using the present invention, the heat value of the sludge can be increased by manual adjustment. Such an increase in the heat value of the sludge may result in the sludge being mixed with one having a higher solids content or as part or all of the sludge mixture contained or stored separately in one or more storage hoppers. This can be done by using a high carbon content sludge, such as a paper mill sludge with a high fiber content.

The variable speed rotary drum / mixer 3 is a cement / mixer operation in which the stirring action of the rotary drum / mixer 3 reduces the size of the particles and facilitates the mixing action of sludge into a homogeneous fluid suitable for pumping. It operates in a similar manner to the method. drum·
Once the required solids content has been achieved in the mixer 3, the sludge is discharged via line 9 to a closed sludge pump suction tank 10.

The sludge pump suction tank 10 stores the desired sludge mixture before it is injected into the furnace. The size of this tank depends on the operating parameters of the particular furnace and whether batch mode or continuous mode is used. The sludge pump suction tank 10 has a variable speed of the drum mixer 3 in order to adjust the flow rate flowing out of the drum mixer 3 in order to maintain a constant level in the sludge pump suction tank 10. A level controller 11 for controlling the drive 12 is provided. Sludge
The pump suction tank 10 is also equipped with a mixer 13 for continuously stirring the sludge in order to prevent the sludge from solidifying or condensing in order to maintain a homogeneous fluid state.

The sludge is fed from the bottom of the suction tank 10 through a line 14 into a conditioner 15 that crushes and shears all large chunks of material before entering a variable speed progressive cavity pump 16. (In other embodiments where the sludge is pumped directly from the customer or from a supply truck, the conditioner may be moved to minimize damage from large particle contaminants from the customer. Yes, and additional conditioners can be installed in the containment line.) One feature of the invention is that diluting sludge can flow relatively easily, thereby allowing the use of progressive cavity pumps. Is. Prior art devices for pumping sludge with high solids content, i.e. sludges with 15-25% solids content, had to use a powerful piston pump, or a reciprocating pump that was expensive and difficult to maintain. . The progressive cavity pump of the present invention is
It has good performance and can easily handle sludge with a solids content up to about 15%.

The pump 16 is driven by a variable speed drive 17 and is capable of discharging sludge through line 18 and feeding a feed circulation line 26 for return to the suction tank 10 and also a furnace 20. It can also be fed to the sludge atomizing nozzle 19 for injection into the combustion zone 24 of

The purpose of the recirculation line 26 is to prevent excessive pressure from being generated in the line 18 to the furnace 20 when the amount of sludge supplied to the furnace is low, while still allowing the pump to comply with the pump manufacturer's specifications. To maintain proper flow through 16. In the case of some pumps, the pump may overheat if the flow through the pump is too slow. In addition, the recirculation return to suction tank 10 facilitates continuous agitation of the sludge when there is no flow to the furnace. It is desirable to provide a recirculation line 26. However, if the pump 16 has some form of minimum flow and maximum pressure control, and the suction tank 10 does not recirculate and maintains sufficient sludge agitation, then the recirculation line 26 may be used. It can be omitted.

The recirculation line 26 comprises a flow controller 25 that adjusts the recirculation control valve 27 to ensure an adequate minimum flow and to stabilize the nozzle sludge pressure. When the demand for sludge injection to the furnace 20 is small, the flow rate controller 25
Has opened the recirculation control valve 27 to maintain a minimum flow rate and steady pressure, allowing the sludge to return to the suction tank 10 by recirculation, thereby preventing overheating of the pump 16.

The sludge flow rate to the furnace 20 is controlled by a programmable controller 21 in response to a demand signal from a furnace temperature controller 22 based on the temperature of the furnace flue gas. When the temperature of the furnace rises above the set point set by the programmable controller 21, the flow controller 23 adjusts the speed of the variable speed drive 17. The drive 17 preferably controls the speed of the pump 16 and the flow of sludge to the nozzle 19 so that the sludge is atomized by the steam and sprayed into the combustion zone 24 of the furnace 20.

Although it is possible to use other injection methods, it is preferable to use steam atomization. Because the hot steam preheats the sludge and is also floating
This is because it has the effect of dispersing the sludge into fine particles so that it will burn almost completely. Also, advances in pump technology and / or preheating and resulting reduction in sludge viscosity may allow higher solids content sludge to be pumped through the device to the full injection nozzle. In this case, the atomized steam can act as a dilution medium, which eliminates the need to pre-dilute the sludge. Therefore, when using vapor atomization, sludge dilution can be done later at the injection nozzle instead of at the sludge receiving / treatment module.

As shown in FIG. 1, steam is piped through line 29 from steam header 28 to pressure control valve 30. In the case of a furnace device that does not generate steam inside,
Steam can be supplied from an external source. In either device, a programmable controller 21 regulates a pressure control valve 30 at the nozzle 19 to maintain a set differential pressure between steam and sludge. Testing has shown that the optimum differential pressure depends on the solids content and other sludge characteristics.
For example, a sludge having a solids content of about 10% has a minimum vapor pressure at the nozzle of 50 psig and a minimum sludge pressure of 25 psig of about 3 gallons per minute of atomized sludge. It turns out that the flow can be maintained. Higher pressure at the nozzle is used for higher flow rates. As a result, dry solids sludge treatment rates of up to 5% can be achieved relative to the MSW treatment capacity.

The sludge injection nozzle 19 is selected because it allows steam to be injected into the sludge stream before the injection point of the nozzle. This selection allows preheating of the sludge and partial flash drying, and the setting of additional energy release stages at the nozzle injection points. With this configuration, in particular, the size of the sludge particles can be minimized so that almost complete combustion can be surely performed in a floating state in the combustion zone 24 of the furnace 20. In the case of the conventional invention, a part of the large sludge particles could be dropped into the bottom ash device 31.
Larger particles tend to burn incompletely, resulting in higher deposition of unburned material in the bottom ash. If so, the bottom ash may have an unfavorable chemical composition when tested for compliance with environmental regulations. Floating combustion ensures that each sludge particle burns almost completely, but in this case, fly ash is
Departed from the furnace 20 at duct 32 and sent to an air pollution control device which is configured to treat all fly ash products of combustion while fully complying with regulations.

The sludge injection nozzle 19 is also specifically configured with a wide free cross section, preferably at least 0.365 square inches, in order to minimize the possibility of clogging. ing. Further, it is preferable that a protruding spiral portion is provided at the discharge end, and the sludge is spirally discharged from the nozzle by the spiral portion. Therefore, the superheated sludge discharged in a spiral shape is not injected in a straight line, but is injected in a circular shape at a certain speed, consuming more kinetic energy at the nozzle, and sludge particles inside the furnace. Are prevented from colliding with each other, thereby further promoting floating combustion of sludge particles. A suitable sludge atomizing nozzle is Bete F, located in Greenfield, Massachusetts.
There is Bete Model SA2100 commercially available from og Nozzle.

The location of the sludge injection point will depend on the sludge characteristics of the particular application and the furnace configuration. The preferred sludge injector is configured to be flexible to the application. Therefore, the position of the injection point is determined taking into account the possibility of solving the problem while satisfying the requirements for good combustion such as residence time, furnace outlet temperature and complete turbulence.

The preferred sludge treatment and injection system is configured to simply interface with current furnace combustion control systems. Programmable to establish steam flow before sludge flow and automatically shut off sludge flow in case of malfunctions such as steam flow drop in nozzle or fuel trip of boiler The controller 21 is provided with a relay. No air is supplied with the sludge. Therefore, the interface to the combustion air control system can be simple. The heat from the atomized steam plus the heat value of the sludge offsets the heat loss due to the evaporating liquid in the sludge. Therefore, current combustion air control systems need only be slightly biased or require no compensation when the preferred sludge injector is running.

Conventional sludge combustors have focused on introducing sludge with a high solid content into the furnace. This is because it has been known that injecting sludge having a low solid content and a high water content into the furnace lowers the temperature of the furnace. If the other factors are constant, there will be a net heat loss of the furnace due to the energy required to evaporate the water in the sludge. Therefore, in order to produce sludge that does not adversely affect the temperature of the furnace, elaborate steps are often performed to prevent heat loss from the sludge, such as dewatering and preheating. Multiple steps are also carried out to enrich the combustion chamber with the aim of minimizing the heat loss in the furnace.

The present invention employs a seemingly contradictory method of increasing the water content of the input sludge. By increasing the water content, the device can handle sludge in a more efficient and cost-effective way. Furthermore, the cooling effect obtained by injecting high water content sludge into the municipal waste combustion furnace can be compensated by increasing the input of the municipal solid waste. The cooling effect described above can also be compensated for by increasing the turbulence in the furnace and by using the oxygen consumed by utilizing the less agitated turbulence. Therefore, by controlling the temperature of the furnace in this way, the solid waste input can be increased and thereby the revenue of the MWC facility can be increased.

Furthermore, injecting sludge with a high water content to lower the temperature of the flame of the furnace has the surprising effect of reducing the level of NOx emission from the furnace. Therefore, the present invention also has potential as an air pollution control device that generates revenue and reduces NOx.

The preferred sludge treatment and injection device described above is not limited by any type of boiler or fuel type and has the potential to open up a whole new path to solving difficult combustion problems. Mass incineration MWC often suffers from slagging problems due to high temperature melting of ash. In that case, the preferred sludge injector described above can cool areas of interest to reduce slugging. The preferred sludge injector described above can also minimize erosion problems due to localized hot chloride corrosion in the waste fuel MWC by improving turbulence, mixing and temperature control. Although conventional fossil fuel boilers also suffer from various slugging and corrosion, the preferred sludge injector of the present invention can also be used to solve these problems. All boilers are subject to increasingly stringent pollution control regulations. The preferred sludge injector of the present invention also has the potential to provide a new method of controlling emissions while at the same time solving local sludge treatment problems.

Example The apparatus of the present invention was tested, in which case diluted paper and sewage sludge were injected into a conventional operating municipal waste combustor.

The fuel facilities selected for testing each have three mass incineration refractory MWCs capable of processing 120 tons per day. In normal operation, two fuel systems are in operation and one is in standby. The fuel system is connected to two waste heating boilers and associated air pollution control trains. Each air pollution control train consists of an electrostatic precipitator and a spray absorber. The selected facility can incinerate up to 240 tons of municipal solid waste (MSW) per day,
At 230 psig and 500 ° F., generate 60,000 pounds of superheated steam for sale.

The current fuel system facility was modified slightly so that sludge could be received, diluted, mixed, stored, and pumped. A 1800 gallon capacity plastic mixing tank was installed in the facility and a Nemo progressive pump with variable speed drive from Nietzsch was connected to the mixing tank. The capacity of the pump used is 6
At a speed of 0 rpm it was about 100 gallons per minute. However, for this test, the speed was reduced to about 10 rpm to achieve the required sludge flow. A sludge recirculation device was installed that could recirculate a certain amount of sludge and return it from the pump discharge to the mixing tank. During this test, control of pressure and flow rate by the recirculation system was done manually. One of the facility's fuel system units has also been modified to allow the sludge to be sprayed into the fuel system and atomized by steam. Beta Fog N
Install the ozzle (same model # SA2100 as above) as close as possible to the active fuel zone in the fuel system and control the sludge flow rate with steam header and nozzle pressure, sludge header and nozzle pressure, and magnetic flow meters A spray panel was used so that This nozzle was chosen because it had a large flow area (0.3 mm) to minimize the possibility of clogging by sludge particles.
65 square inches).

Sludge with a solids content of about 24-40% was received in the on-site drum and roll-off containers. The sludge was manually placed in a mixing tank that was prefilled with the amount of water needed to dilute this type of sludge to the required final solids content. A propeller-type mixer was used to agitate and mix the sludge injector in the tank, and the cavity pump was first operated in a manual recirculation mode to further aid in grinding the sludge mass.

Diluted sludge containing solids ranging from 2% to about 12% was prepared and tested. It was concluded that at a solids content of about 10%, the combination of handling and treatment properties in the furnace was the best. Tests were carried out with a sludge flow rate of 4-20 GPM and 10 GPM was selected as the optimum flow rate. The selected flow rate, 10 GPM, represents a 5% dry solids sludge disposal ratio to the facility's MSW disposal capacity. This level demonstrates that all solid waste and sewage sludge generated in normal communities can be disposed of together.

Dilution sludge is in the range of 15-25 psig where the sludge is atomized by the cavity pump at a temperature of about 390 ° F. and at a pressure in the range similar to the sludge pressure, by the steam supplied to the nozzle. Was supplied to the injection nozzle at a pressure of. The start of sludge injection into the fuel system was expected due to a few degrees of furnace temperature increase for a short time before injection. This means that in order to supply more heat to the fuel system,
This was done by slightly increasing the MSW feed rate.

Test data was collected with current plant instrumentation. Data collection stations were installed in the main control room, sludge mixing / pumping station, sludge injection station, and continuous discharge monitor room. With the infrared camera and monitor installed in the main control room, the state of the primary fuel system could be visually observed. Infrared technology has been particularly useful in determining the state of atomization within the fuel system. At the end of each test, a sample of bottom ash was taken from the burnout grid just prior to placement in the bottom ash handling and equipment. A sample was taken from the top of the ash bed to reflect the worst case.

During sludge injection, an infrared camera located in the primary fuel system detected white spots above the MSW incineration grid and increased turbulence in the fuel system. Combustion MSW became brighter when sludge injection was performed, indicating that the turbulence due to the injected sludge improved mixing and thus improved combustion conditions in the furnace. The low amount of excess oxygen during sludge combustion may be due to the turbulent flow in the furnace due to the injectors, which used the excess air in the chamber more efficiently. Furthermore, when the diluted sludge was injected into the combustor, there was no effect on the ventilation of the furnace.

Throughout the entire program of the test, no sulfur dioxide (SO ₂ ) was detected in the gas emitted from the stack with or without co-combustion of the sludge. Similarly,
The test results showed that carbon monoxide (CO) emissions were virtually zero with and without co-combustion. This is important. This is because the fact that CO is not contained is a major indicator of good combustion conditions that do not emit dioxin. Occasionally small spikes showing CO emissions can be observed, but these spikes do not approach the facility's acceptable levels and M
It is usually observed when 100% of SW is burned. Therefore, co-combustion of sludge had no effect on SO ₂ and CO emissions.

Surprisingly, however, initial tests of various sludge parameters showed that nitrous oxide (NO _x ) emissions were immediately and continuously reduced. By lowering the temperature of the flame, it is well known that it is possible to reduce the NO _X emission. However, such reductions can also increase CO due to incomplete combustion. Therefore, good combustion is, NO _X and CO emissions is included in the least becomes region. Throughout all sludge injection tests, CO emissions are close to zero,
Reduction of the NO _X by the test program was believed significant. Table 1 below outlines these test results.

[0060]

[Table 1]

Similar tests were conducted for particulate, metal and dioxin / furan release and found that the releases were all below the acceptable parameters. Ash samples were also collected during the experiment to determine the effect of co-combustion of MSW and sludge on ash quality. The results are consistent and show a slight increase in ignition loss when compared to the average value of 1.1-1.2%, but very low numbers indicating good combustion.

In summary, the test program is that the present invention is an efficient sludge treatment device that does not adversely affect plant operation, air emissions or ash quality and that can also operate as a furnace temperature control device. showed that. The test program shows that the injection and co-combustion of sludge into a municipal solid waste combustor has the advantage that it can balance the heat value of the municipal solid waste, thereby increasing the throughput of MSW to MWC. There is. Moreover, apparently reducing the emission of NO _X.

While the embodiments of the present invention have been described with reference to the accompanying drawings, the present invention
It is to be understood that it is not limited to such precise embodiments, and that one of ordinary skill in the art can make other changes and modifications without departing from the scope and spirit of the invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a preferred sludge treatment and injection device of the present invention.

[Explanation of symbols]

    1 hopper     2 screw conveyor     3 Variable rotating drum mixer     4 lines     5 Solid component transfer device     6 Solid controller     7 Variable speed drive     8 dilution valve     9 lines   10 Sludge pump suction tank   11 level controller   12 variable speed drive   13 mixer   14 lines   15 conditioner   16 Sequential feed cavity pump   17 Variable speed drive   18 lines   19 Supply sludge atomizing nozzle   20 furnaces   21 Controller   22 Furnace temperature controller   23 Flow controller   24 Burning zone   25 Flow controller   26 Recirculation line   27 Recirculation control valve   28 steam headers   29 lines   30 Pressure control valve   31 Bottom ash device   32 ducts 100 Sludge treatment and injection equipment 200 Sludge receiving / treatment module 300 sludge injection / combustion module

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 11/06 C02F 11/06 BF23G 5/44 F23G 5/44 B 5/50 5/50 GM ( 81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, C , CN, CR, CU, CZ, DE, DK, DM, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE , SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, UZ, VN, YU, ZA, ZW (72) Inventor Kevin Gee Rousseau USA Massachusetts 01247 Windsor・ Bates Road ・ 213 F Term (reference) 3K062 AA24 AB01 AC02 BA02 CA01 DA08 DA11 DB01 DB28 3K065 AA24 AB01 AC02 BA01 EA04 EA06 EA23 EA31 EA42 EA44 4D059 AA03 AA30 BB01 EA01 CB01 EA02 EA01 CB01 EA02 CB02 EA02

Claims (37)

[Claims] 1. An apparatus for co-combusting sludge in a combustor, the sludge receiving / treating module for receiving sludge and diluting the sludge with a liquid, thereby increasing the water content of said sludge. And a sludge injection / combustion module for injecting the diluted sludge into the combustion zone of a combustor when the diluted sludge is incinerated in a floating state in the combustor. . 2. The apparatus of claim 1, wherein the sludge injection / combustion module atomizes the diluted sludge with steam and sprays the atomized diluted sludge into the combustion zone of the combustor. An apparatus comprising a nozzle. 3. The apparatus of claim 1, wherein the combustor is a municipal solid waste combustor, within which the diluted sludge is incinerated in a floating state over the municipal solid waste. A device characterized by. 4. The apparatus according to claim 1, further monitoring the temperature in the combustion device, and changing the amount of diluted sludge injected into the combustion device according to the change in the temperature in the combustion device. An apparatus comprising a controller for causing the device. 5. The apparatus according to claim 1, wherein the sludge receiving / treatment module receives a hopper for receiving and storing the sludge, and a sludge for receiving the sludge from the hopper and a liquid source. A mixer for mixing the sludge with the liquid, thereby diluting the sludge. 6. The apparatus according to claim 5, wherein the liquid supply source is a wastewater supply source. 7. The apparatus of claim 5, wherein the liquid source is an air pollution control liquid source. 8. The apparatus of claim 5, further comprising monitoring the solids content of the diluted sludge in the mixer, the amount of sludge received from the hopper, and the amount of liquid received from the liquid source. An apparatus comprising a solid state controller for changing the. 9. The apparatus according to claim 8, further comprising: continuously monitoring a solid content of the diluted sludge in the mixer, and further monitoring the solid content in the mixer according to a change in the solid content in the mixer. A solid content transmitter connected to the mixer to generate a signal, and fixed within the hopper to supply the sludge from the hopper to the mixer in response to the signal generated by the solid state controller. And a dilution valve connected to the liquid supply source for supplying the liquid from the liquid supply source to the mixer in response to a signal generated by the solid state controller. apparatus. 10. The apparatus of claim 9, wherein the mixer is a drum mixer and the conveyor is a screw conveyor. 11. The apparatus of claim 2, wherein the sludge injection / combustion module further comprises a sludge tank for receiving and storing the diluted sludge from the sludge receiving / treatment module, and the sludge for the sludge. An apparatus comprising a pump in fluid connection with the sludge tank and the injection nozzle for feeding from the tank to the injection nozzle. 12. The apparatus of claim 11, wherein the sludge tank monitors the level of sludge in the sludge tank and maintains the sludge in the sludge tank at a constant level. A level controller for generating a signal to the sludge receiving / treatment module to vary the amount of sludge received in the sludge tank, and to continuously agitate the sludge in the sludge tank Mixer, a discharge line for sending the sludge from the sludge tank to the pump, and a conditioner inserted in the discharge line to shatter the sludge before entering the pump. An apparatus comprising: 13. The apparatus of claim 11, wherein the sludge injection / combustion module is further connected between the pump and the sludge tank for recirculating sludge back to the sludge tank. A recirculation line, and a recirculation control valve connected to the recirculation line to control the flow rate of sludge through the recirculation line, and monitoring the sludge flow rate through the pump, A flow controller connected to the pump to generate a signal to the recirculation control valve for the purpose of varying the amount of sludge flowing through the recirculation line. 14. The apparatus of claim 11, wherein the sludge injection / combustion module further monitors the temperature within the combustor and generates a signal in response to temperature changes within the combustor. An apparatus comprising a controller and a pump driver connected to the pump for varying the flow rate of sludge through the pump in response to a signal received from the temperature controller. 15. The apparatus of claim 2, wherein the injection nozzle comprises a discharge end for spraying the atomized dilution sludge into the combustion zone of the combustion device, the dilution sludge being the nozzle. Before being sprayed on the discharge end of
A device characterized by being atomized by steam and preheated. 16. The apparatus of claim 15, wherein the discharge end of the injection nozzle is configured to spirally discharge sludge from the nozzle. 17. An apparatus for co-combusting sludge in a municipal solid waste combustor for receiving sludge and diluting sludge with liquid, thereby increasing the water content of said sludge. A sludge receiving / treatment module, and a sludge injection nozzle for atomizing the diluted sludge with steam and spraying the atomized diluted sludge into a combustion zone of a combustor for incinerating municipal solid waste therein. A device characterized by the above. 18. The apparatus according to claim 17, further comprising: monitoring the temperature in the combustion device and injecting the atomized diluted sludge into the combustion device in response to a change in the temperature in the combustion device. An apparatus comprising a controller for changing the. 19. The apparatus of claim 17, wherein the sludge receiving / treatment module receives a hopper for receiving and storing the sludge, the sludge from the at least one hopper, and the liquid from a liquid source. A mixer for mixing the sludge with the liquid, thereby diluting the sludge. 20. The apparatus of claim 19, wherein the liquid source is a wastewater source. 21. The apparatus of claim 19, wherein the liquid source is an air pollution control liquid source. 22. The apparatus of claim 19, further comprising monitoring the solids content of the diluted sludge in the mixer to determine the amount of sludge received from the hopper and the amount of liquid received from the liquid source. An apparatus comprising a solid state controller for changing the. 23. The apparatus according to claim 22, further comprising: continuously monitoring a solid content of the diluted sludge in the mixer, the solid controller being adapted to change the solid content in the mixer. A solid content transmitter connected to the mixer for generating a signal, and fixed within the hopper for supplying the sludge to the mixer from the hopper in response to the signal generated by the solid state controller And a dilution valve connected to the liquid source for supplying the liquid from the liquid source to the mixer in response to a signal generated by the solid state controller. Device to do. 24. The apparatus of claim 17, further comprising a sludge tank for receiving and storing the diluted sludge from the sludge receiving / treatment module; and sending the sludge from the sludge tank to the injection nozzle. To this end, an apparatus is provided, which comprises a pump fluidly connected to the sludge tank and the injection nozzle. 25. The apparatus of claim 24, wherein the sludge tank monitors the level of sludge in the sludge tank and maintains the sludge in the sludge tank at a constant level. A level controller for generating a signal to the sludge receiving / treatment module to vary the amount of sludge received in the sludge tank, and to continuously agitate the sludge in the sludge tank A mixer, a discharge line for sending the sludge from the sludge tank to the pump, and a conditioner inserted in the discharge line to grind the sludge before entering the pump. An apparatus characterized by comprising. 26. The apparatus of claim 24, further comprising a recirculation line connected between the pump and the sludge tank for recirculating sludge back to the sludge tank. A recirculation control valve connected to the recirculation line to control the flow rate of the sludge through the recirculation line, and a sludge flowing through the recirculation line for monitoring the sludge flow rate through the pump. And a flow controller connected to the pump to generate a signal to the recirculation control valve for the purpose of varying the amount of discharge flow. 27. The apparatus according to claim 24, further comprising: a temperature controller for monitoring a temperature in the combustion apparatus and generating a signal in response to a temperature change in the combustion apparatus, and receiving from the temperature controller. A pump driver connected to the pump for varying the flow rate of sludge through the pump in response to the signal. 28. The apparatus of claim 17, wherein the injection nozzle has a discharge end for spraying the atomized dilution sludge into the combustion zone of the combustor, the dilution sludge comprising: A device characterized by being atomized by steam and preheated before being sprayed from the discharge end of the nozzle. 29. The apparatus of claim 28, wherein the discharge end of the injection nozzle is configured to spirally discharge sludge from the nozzle. 30. A method for co-combusting sludge in a combustor, the method comprising: diluting sludge with a liquid, thereby increasing the water content of the sludge; A method comprising: injecting into a combustion zone and combusting the diluted sludge in a suspended state within the combustor. 31. The method of claim 30, further comprising atomizing the diluted sludge with steam before injecting into the combustion zone. 32. The method of claim 30, wherein the combustor is a municipal solid waste combustor and the diluted sludge is incinerated in a floating state over the municipal solid waste. Method. 33. The method of claim 30, further comprising: monitoring a temperature within the combustion device; and controlling the temperature of the combustion device in response to temperature changes within the combustion device. Varying the amount of diluted sludge injected therein. 34. The method of claim 30, wherein the liquid is wastewater. 35. The method of claim 30, wherein the liquid is an air pollution control slurry. 36. The method of claim 30, further comprising: monitoring the solids content of the diluted sludge; varying the amount of sludge and liquid in response to changes in the solids content of the diluted sludge. A method comprising :. 37. The method of claim 30, further comprising agitating the diluted sludge, thereby reducing the size of the particles in the sludge, and the required uniform homogeneity suitable for pumping. Mixing the diluted sludge into a state.